Reports

Hi All !!

I've been working with Dolphin learning it a time ago.
I like it but I have questions about it.
My principal activity is consulting and development of Business Aplications.
I am currently working with Progress but I am considering
using Smalltalk (may be Dolphin , may be other) to develop this kind of
systems.
One of my doubts was how  to make persistent objects in a multiple user
application.
I realize that i can use RDBMS but really i don't like this solution.
I bougth OmniBase and I am now working in a framework upon it. Then i hope
to solve the persistence problem for small to mid size applications.
But now i am thinking how to make reports (some of then complex ones) with a
quality presentation and in a standart format.
May be PDF , word , excell , etc.There is some product can hep me ?

I need feedback for all people who have solved this problem. I want to know
how they solve this.
I need information if there is a royalty free (not free ) product in order
to help me or any other solution , information source , white papers
or ideas that anyone can consider usesfull.

TIA
Pablo Digonzelli

PD: Sorry for my english.

Pablo,
    You could use Crystal Reports.


    Ron


pablo digonzelli wrote in message
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"pablo digonzelli" <[hidden email]> wrote in message
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> My principal activity is consulting and development of Business
Aplications.

Me too.  I am working mainly on a medical accounting (accounts
receivable/electronic claims) system currently.  It was written originally
in DOS/Clipper.  I have rewritten it in Dolphin.  We are nearing the end of
our beta cycle and on the verge of putting into production.

> One of my doubts was how  to make persistent objects in a multiple user
> application.
> I realize that i can use RDBMS but really i don't like this solution.

What I am doing is using Python/MetaKit (both free and open source) for the
database server, both solid as a rock.  This is the only process that
touches the data directly and, even though it typically runs on a Windows
machine, could run on a Linux or other Unix box instead for a client who
wanted a more reliable server.  The Dolphin front-ends communicate with the
Python/MetaKit server via TCP/IP.  I have written an Object<-->Relational
mapping layer in Dolphin that takes care of "materializing" the Patients,
LedgerEntries, etc. as needed.  I based this largely on the OR mapping
described in Chamond Liu's book.

Had I to do this all over, I would very seriously consider a simpler
approach of holding all the business objects in RAM (or virtual RAM) within
a central Smalltalk image ("all objects, all the time" so to speak) with, of
course, the ability to dump and load the objects to and from the disk, keep
a log on disk of transactions, and have the ability to recover at any point
by playing the log against the last good dump.  As happy as I am with Python
and MetaKit, there is still a price to be paid mentally and
productivity-wise in switching between languages/environments.

This approach of holding all the objects in RAM might not work for everyone
<wink>.  One factor is the size of your data and another is whether clients
are agreeable to setting up a server with sufficient RAM.  On the other
hand, I recently saw an ad for 256 MB of RAM for $79 or so.  If the client
cannot afford $79 for 256 MB for a single machine (the server), then how can
I expect that client to afford to pay me?  QED.

Using the above approach, the next part would be to add a simple distributed
Smalltalk facility whereby very little data would be transferred to the
Dolphin client programs, mainly just the result of #displayString for the
objects to be displayed on the screen.  All the business objects and
collections thereof would remain only on the server.

(You might note the similarity of the above to a web-server based
application with web browsers for the client.  This is another strong
candidate, as Dolphin could generate the HTML very nicely.)

I hope to play with that for fun.  Meanwhile, the approach of Python/MetaKit
for the server and Dolphin for the clients is working fine for me.

> But now i am thinking how to make reports (some of then complex ones) with
a
> quality presentation and in a standart format.
> May be PDF , word , excell , etc.There is some product can hep me ?

I am doing the reports with straightforward Windows canvas programming.
Various examples appear in the Dolphin newsgroup archives.  It is easy to
write a simple report framework that takes care of page breaks, headers,
footers, etc.  Subclass that for your reports, just supplying the
header/footer/detail-line text (or blocks to generate the text) and a
collection to iterate over.  I am quite happy with this approach.  (Again,
generating HTML for reports or generating Postscript (LaTex, Lout, etc.) are
alternatives which are very easily done in Dolphin.  Once in Postscript
there are converters to PDF.)

I am very happy with Dolphin and the Dolphin people.  The only problem with
Dolphin is that it is connected to Windows and thus is contaminated (fruit
of the poisoned tree).  I swing madly back and forth between being mildly
irritated with Windows and Microsoft and being very irritated.

> PD: Sorry for my english.

Please do not ever apologize for your English.  I myself am multi-lingual,
speaking both Texan and some form of American English.

-- Frank
[hidden email]